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Hou M, Opedal ØH, Zhao ZG. Sexually concordant selection on floral traits despite greater opportunity for selection through male fitness. THE NEW PHYTOLOGIST 2024; 241:926-936. [PMID: 37899633 DOI: 10.1111/nph.19370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 10/16/2023] [Indexed: 10/31/2023]
Abstract
Pollinators are important drivers of floral trait evolution, yet plant populations are not always perfectly adapted to their pollinators. Such apparent maladaptation may result from conflicting selection through male and female sexual functions in hermaphrodites. We studied sex-specific mating patterns and phenotypic selection on floral traits in Aconitum gymnandrum. After genotyping 1786 offspring, we partitioned individual fitness into sex-specific selfed and outcrossed components and estimated phenotypic selection acting through each. Relative fitness increased with increasing mate number, and more so for male function. This led to greater opportunity for selection through outcrossed male fitness, though patterns of phenotypic selection on floral traits tended to be similar, and with better support for selection through female rather than male fitness components. We detected directional selection through one or more fitness component for larger flower number, larger flowers, and more negative nectar gradients within inflorescences. Our results are consistent with Bateman's principles for sex-specific mating patterns and illustrate that, despite the expected difference in opportunity for selection, patterns of variation in selection across traits can be rather similar for the male and female sexual functions. These results shed new light on the effect of sexual selection on the evolution of floral traits.
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Affiliation(s)
- Meng Hou
- College of Ecology, Lanzhou University, 730000, Lanzhou, China
- Key Laboratory of Wetland Ecology and Environment, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 130102, Changchun, China
| | | | - Zhi-Gang Zhao
- College of Ecology, Lanzhou University, 730000, Lanzhou, China
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2
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Lavaut E, Valero M, Mauger S, Guillemin ML, Destombe C, Dufay M. Sexual selection in seaweed? Testing Bateman's principles in the red alga Gracilaria gracilis. Proc Biol Sci 2023; 290:20231668. [PMID: 37700657 PMCID: PMC10498045 DOI: 10.1098/rspb.2023.1668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 08/21/2023] [Indexed: 09/14/2023] Open
Abstract
In anisogamous species, sexual selection is expected to be stronger in males. Bateman's principles state that the variance in (i) reproductive and (ii) mating success is greater for males, and (iii) the relationship between reproductive success and mating success (the Bateman gradient) is also stronger for males than for females. Sexual selection, based on Bateman's principles, has been demonstrated in animals and some angiosperms, but never in a seaweed. Here we focus on the oogamous haploid-diploid rhodophyte Gracilaria gracilis in which previous studies have shown evidence for non-random mating, suggesting the existence of male-male competition and female choice. We estimated mating and reproductive success using paternity analyses in a natural population where up to 92% of fertilizations occurred between partners of that population. The results show that the variance in mating success is significantly greater in males than in females and that the Bateman gradient is positive only in males. Distance to female partners also explains a minor part of the variance in male mating success. Although there is no evidence for sexual dimorphism, our study supports the hypothesis that sexual selection occurs in G. gracilis, probably on male traits, even if we cannot observe, characterize or quantify them yet.
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Affiliation(s)
- E. Lavaut
- IRL EBEA 3614, Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, Pontificia Universidad Católica de Chile, Universidad Austral de Chile, Station Biologique de Roscoff, CS 90074, Place Georges Teissier, 29688 Roscoff cedex, France
| | - M. Valero
- IRL EBEA 3614, Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, Pontificia Universidad Católica de Chile, Universidad Austral de Chile, Station Biologique de Roscoff, CS 90074, Place Georges Teissier, 29688 Roscoff cedex, France
| | - S. Mauger
- IRL EBEA 3614, Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, Pontificia Universidad Católica de Chile, Universidad Austral de Chile, Station Biologique de Roscoff, CS 90074, Place Georges Teissier, 29688 Roscoff cedex, France
| | - M. L. Guillemin
- IRL EBEA 3614, Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, Pontificia Universidad Católica de Chile, Universidad Austral de Chile, Station Biologique de Roscoff, CS 90074, Place Georges Teissier, 29688 Roscoff cedex, France
- Núcleo Milenio MASH, Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - C. Destombe
- IRL EBEA 3614, Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, Pontificia Universidad Católica de Chile, Universidad Austral de Chile, Station Biologique de Roscoff, CS 90074, Place Georges Teissier, 29688 Roscoff cedex, France
| | - M. Dufay
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
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Rodríguez-Otero C, Hedrén M, Friberg M, Opedal ØH. Analysis of trait-performance-fitness relationships reveals pollinator-mediated selection on orchid pollination traits. AMERICAN JOURNAL OF BOTANY 2023:e16128. [PMID: 36655508 DOI: 10.1002/ajb2.16128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 07/24/2022] [Accepted: 08/01/2022] [Indexed: 06/17/2023]
Abstract
PREMISE The role of pollinators in evolutionary floral divergence has spurred substantial effort into measuring pollinator-mediated phenotypic selection and its variation in space and time. For such estimates, the fitness consequences of pollination processes must be separated from other factors affecting fitness. METHODS We built a fitness function linking phenotypic traits of food-deceptive orchids to female reproductive success by including pollinator visitation and pollen deposition as intermediate performance components and used the fitness function to estimate the strength of pollinator-mediated selection through female reproductive success. We also quantified male performance as pollinarium removal and assessed similarity in trait effects on male and female performance. RESULTS The proportion of plants visited at least once by an effective pollinator was moderate to high, ranging from 53.7% to 85.1%. Tall, many-flowered plants were often more likely to be visited and pollinated. Given effective pollination, pollen deposition onto stigmas tended to be more likely for taller plants. Pollen deposition further depended on traits affecting the physical fit of pollinators to flowers (flower size, spur length), though the exact relationships varied in time and space. Using the fitness function to assess pollinator-mediated selection through female reproductive success acting on multiple traits, we found that selection varied detectably among taxa after accounting for sampling uncertainty. Across taxa, selection on most traits was stronger on average and more variable when pollination was less reliable. CONCLUSIONS These results support pollination-related trait-performance-fitness relationships and thus pollinator-mediated selection on traits functionally involved in the pollination process.
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Affiliation(s)
| | - Mikael Hedrén
- Department of Biology, Biodiversity Unit, Lund University, SE, 22362, Lund, Sweden
| | - Magne Friberg
- Department of Biology, Biodiversity Unit, Lund University, SE, 22362, Lund, Sweden
| | - Øystein H Opedal
- Department of Biology, Biodiversity Unit, Lund University, SE, 22362, Lund, Sweden
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Losch F, Liedtke S, Vautz W, Weigend M. Evaluation of floral volatile patterns in the genus Narcissus using gas chromatography-coupled ion mobility spectrometry. APPLICATIONS IN PLANT SCIENCES 2023; 11:e11506. [PMID: 36818782 PMCID: PMC9934524 DOI: 10.1002/aps3.11506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 06/18/2023]
Abstract
PREMISE Daffodils (Narcissus, Amaryllidaceae) are iconic ornamentals with a complex floral biology and many fragrant species; however, little is known about floral plant volatile organic compounds (pVOCs) across the genus and additional sampling is desirable. The present study investigates whether the floral scent of 20 species of Narcissus can be characterized using gas chromatography-coupled ion mobility spectrometry (GC-IMS), with the aim of building a comparative pVOC data set for ecological and evolutionary studies. METHODS We used a commercial GC-IMS equipped with an integrated in-line enrichment system for a fast, sensitive, and automated pVOC analysis. This facilitates qualitative and (semi)-quantitative measurements without sample preparation. RESULTS The GC-IMS provided detailed data on floral pVOCs in Narcissus with very short sampling times and without floral enclosure. A wide range of compounds was recorded and partially identified. The retrieved pVOC patterns showed a good agreement with published data, and five "chemotypes" were characterized as characteristic combinations of floral volatiles. DISCUSSION The GC-IMS setup can be applied to rapidly generate large amounts of pVOC data with high sensitivity and selectivity. The preliminary data on Narcissus obtained here indicate both considerable pVOC variability and a good correspondence of the pVOC patterns with infrageneric classification, supporting the hypothesis that floral scent could represent a considerable phylogenetic signal.
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Affiliation(s)
- Florian Losch
- Nees‐Institut für Biodiversität der Pflanzen, Mathematisch‐Naturwissenschaftliche FakultätRheinische Friedrich‐Wilhelmsuniversität Bonn53115BonnGermany
| | - Sascha Liedtke
- ION‐GAS GmbHKonrad‐Adenauer‐Allee 1144263DortmundGermany
| | - Wolfgang Vautz
- ION‐GAS GmbHKonrad‐Adenauer‐Allee 1144263DortmundGermany
- Leibniz‐Institut für Analytische Wissenschaften – ISAS – e.V.Bunsen‐Kirchhoff‐Straße 1144139DortmundGermany
| | - Maximilian Weigend
- Nees‐Institut für Biodiversität der Pflanzen, Mathematisch‐Naturwissenschaftliche FakultätRheinische Friedrich‐Wilhelmsuniversität Bonn53115BonnGermany
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Koski MH. Pollinators exert selection on floral traits in a pollen-limited, narrowly endemic spring ephemeral. AMERICAN JOURNAL OF BOTANY 2023; 110:e16101. [PMID: 36371765 PMCID: PMC10108127 DOI: 10.1002/ajb2.16101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
PREMISE Floral traits are frequently under pollinator-mediated selection, especially in taxa subject to strong pollen-limitation, such as those reliant on pollinators. However, antagonists can be agents of selection on floral traits as well. The causes of selection acting on spring ephemerals are understudied though these species can experience particularly strong pollen-limitation. I examined pollinator- and antagonist-mediated selection in a narrowly endemic spring ephemeral, Trillium discolor. METHODS I measured pollen limitation in T. discolor across two years and evaluated its breeding system. I compared selection on floral traits (display height, petal size, petal color, flowering time) between open-pollinated, and pollen-supplemented plants to measure the strength and mode of pollinator-mediated selection. I assessed whether natural levels of antagonism impacted selection on floral traits. RESULTS Trillium discolor was self-incompatible and experienced pollen limitation in both years of the study. Pollinators exerted negative disruptive selection on display height and petals size. In one year, pollinator-mediated selection favored lighter petals but in the second year pollinators favored darker petals. Antagonist damage did not alter selection on floral traits. CONCLUSIONS Results demonstrate that pollinators mediate the strength and mode of selection on floral traits in T. discolor. Interannual variation in the strength, mode, and direction of pollinator-mediated selection on floral traits could be important for maintaining of floral diversity in this system. Observed levels of antagonism were weak agents of selection on floral traits.
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Affiliation(s)
- Matthew H. Koski
- Department of Biological SciencesClemson UniversityClemsonSouth Carolina29634USA
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Barbot E, Dufaÿ M, Tonnabel J, Godé C, De Cauwer I. On the function of flower number: disentangling fertility from pollinator-mediated selection. Proc Biol Sci 2022; 289:20221987. [PMID: 36448279 PMCID: PMC9709571 DOI: 10.1098/rspb.2022.1987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/03/2022] [Indexed: 12/03/2022] Open
Abstract
In animal-pollinated angiosperms, the 'male-function' hypothesis claims that male reproductive success (RS) should benefit from large floral displays, through pollinator attraction, while female RS is expected to be mainly limited by resource availability. As appealing as this theory might be, studies comparing selection strength on flower number in both sexes rarely document the expected asymmetry. This discrepancy could arise because flower number impacts both pollinator attraction and overall gamete number. In this study, we artificially manipulate floral displays to disentangle the fertility versus pollinator attraction components of selection, both in terms of mating and RS. In females, flower number was under strong fertility selection, as predicted in the absence of pollen limitation. By contrast, in males, flower number was mainly under sexual selection, which in turn increased male RS. However, these selection patterns were not different in males with artificially increased floral displays. This suggests that sexual selection acting on flower number in males does not occur because flower number increases pollinator attraction, but rather because more pollen is available to disperse on more mates. Our study illustrates the power of disentangling various components of selection with potentially sex-specific effects for understanding the evolution of sexual dimorphism.
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Affiliation(s)
- Estelle Barbot
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
- ISEM, Univ. Montpellier, CNRS, IRD, Montpellier, France
| | - Mathilde Dufaÿ
- CEFE, Univ. Montpellier, CNRS, Univ. Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Jeanne Tonnabel
- ISEM, Univ. Montpellier, CNRS, IRD, Montpellier, France
- CEFE, Univ. Montpellier, CNRS, Univ. Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Cécile Godé
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
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Kwok A, Dorken ME. Sexual selection on male but not female function in monoecious and dioecious populations of broadleaf arrowhead ( Sagittaria latifolia). Proc Biol Sci 2022; 289:20220919. [PMID: 36350202 PMCID: PMC9653219 DOI: 10.1098/rspb.2022.0919] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 10/12/2022] [Indexed: 09/30/2023] Open
Abstract
Direct measures of sexual selection in plants are rare and complicated by immobility and modular growth. For plants, instantaneous measures of fitness typically scale with size, but covariances between size and mating success could obscure the detection of sexual selection. We measured the magnitude of sexual selection in a monoecious and a dioecious population of the clonal plant Sagittaria latifolia using Bateman gradients (ßss). These gradients were calculated using parentage analysis and residual regression to account for the effects of shoot and clone size on mating and reproductive success. In both populations, (i) there was greater promiscuity via male function than via female function and (ii) ßss were positive, with significant associations between mating and reproductive success for male but not female function. Moreover, estimated βss were similar for the monoecious and dioecious populations, possibly because non-overlapping female and male sex phases in hermaphroditic S. latifolia reduced the scope for interference between sex functions during mating. This study builds on previous studies of selection on plant mating traits, and of sexual selection under experimental conditions, by showing that sexual selection can operate in natural populations of plants, including populations of hermaphrodites.
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Affiliation(s)
- Allison Kwok
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada K9J 0G2
| | - Marcel E. Dorken
- Department of Biology, Trent University, Peterborough, ON, Canada K9J 0G2
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Chen K, Pannell JR. Disruptive selection via pollinators and seed predators on the height of flowers on a wind-dispersed alpine herb. AMERICAN JOURNAL OF BOTANY 2022; 109:1717-1729. [PMID: 36194694 PMCID: PMC9828390 DOI: 10.1002/ajb2.16073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 06/28/2022] [Indexed: 05/25/2023]
Abstract
PREMISE Floral stalk height is known to affect seed dispersal of wind-dispersed grassland species, but it may also affect the attractiveness of flowers and fruits of animal-pollinated and animal-dispersed plants. Stalk height may thus be responsive to selection via interactions with both mutualist pollinators and seed dispersers, but also antagonist florivores and seed predators. In this study, we aimed to determine the effect of pollinators and seed predators on selection on floral stalk height in the insect-pollinated and wind-dispersed, alpine, andromonoecious herb Pulsatilla alpina, whose flowers also vary in their sex allocation and thus in the resources available to both mutualists and antagonists. METHODS We measured the resource status of individuals in terms of their size and the height of the vegetation surrounding plants of P. alpina at 11 sites. In one population, we recorded floral stalk height over an entire growing season and investigated its association with floral morphology and floral sex allocation (pistil and stamen number) and used leaf-removal manipulations to assess the effect of herbivory on floral stalk height. Finally, in four populations, we quantified phenotypic selection on floral stalk height in four female components of reproductive success before seed dispersal. RESULTS Stalk height was positively associated with female allocation of the respective flower, the resource status of the individual, and the height of the surrounding vegetation, and negatively affected by leaf removal. Our results point to disruptive selection on stalk height in terms of both selection differentials and selection gradients for fertilization, seed predation, and seed maturation rates and to positive selection on stalk height in terms of a selection differential for mature seed number. CONCLUSIONS Stalk height of P. alpina is a costly trait that affects female reproductive success via interactions with both mutualists and antagonists. We discuss the interplay between the resource status and selection imposed on female reproductive success and its likely role in the evolution of sex-allocation strategies, especially andromonoecy.
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Affiliation(s)
- Kai‐Hsiu Chen
- Department of Ecology and EvolutionUniversity of LausanneBiophore Building1015LausanneSwitzerland
| | - John R. Pannell
- Department of Ecology and EvolutionUniversity of LausanneBiophore Building1015LausanneSwitzerland
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Simón‐Porcar VI, Muñoz‐Pajares AJ, de Castro A, Arroyo J. Direct evidence supporting Darwin's hypothesis of cross-pollination promoted by sex organ reciprocity. THE NEW PHYTOLOGIST 2022; 235:2099-2110. [PMID: 35596603 PMCID: PMC9546006 DOI: 10.1111/nph.18266] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/09/2022] [Indexed: 05/28/2023]
Abstract
The floral phenotype plays a main role in the attraction and fit of pollinators. Both perianth traits and the positioning of sex organs can be subjected to natural selection and determine nonrandom mating patterns in populations. In stylar-polymorphic species, the Darwinian hypothesis predicts increased mating success between individuals with sex organs at equivalent heights (i.e. with higher reciprocity). We used paternity analyses in experimental populations of a stylar-dimorphic species. By comparing the observed mating patterns with those expected under random mating, we tested the effects of sex organ reciprocity and perianth traits on mating success. We also analysed phenotypic selection on perianth traits through female and male functions. The (dis)similarity of parental perianth traits had no direct effects on the mating patterns. Sex organ reciprocity had a positive effect on mating success. Narrow floral tubes increased this effect in upper sex organs. Perianth traits showed little signs of phenotypic selection. Female and absolute fitness measures resulted in different patterns of phenotypic selection. We provide precise empirical evidence of the Darwinian hypothesis about the functioning of stylar polymorphisms, demonstrating that mating patterns are determined by sex organ reciprocity and only those perianth traits which are critical to pollinator fit.
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Affiliation(s)
| | - A. Jesús Muñoz‐Pajares
- Department of GeneticsUniversity of GranadaE‐18071GranadaSpain
- Research Centre in Biodiversity and Genetic Resources (CIBIO)Campus Agrário de Vairão4485‐661VairãoPortugal
| | - Alejandra de Castro
- Department of Plant Biology and EcologyUniversity of SevilleE‐41080SevilleSpain
| | - Juan Arroyo
- Department of Plant Biology and EcologyUniversity of SevilleE‐41080SevilleSpain
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Wu Y, Barrett SCH, Duan X, Zhang J, Cha Y, Tu C, Li Q. Herbivore-Mediated Selection on Floral Display Covaries Nonlinearly With Plant-Antagonistic Interaction Intensity Among Primrose Populations. FRONTIERS IN PLANT SCIENCE 2021; 12:727957. [PMID: 34868113 PMCID: PMC8636000 DOI: 10.3389/fpls.2021.727957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
Quantifying the relations between plant-antagonistic interactions and natural selection among populations is important for predicting how spatial variation in ecological interactions drive adaptive differentiation. Here, we investigate the relations between the opportunity for selection, herbivore-mediated selection, and the intensity of plant-herbivore interaction among 11 populations of the insect-pollinated plant Primula florindae over 2 years. We experimentally quantified herbivore-mediated directional selection on three floral traits (two display and one phenological) within populations and found evidence for herbivore-mediated selection for a later flowering start date and a greater number of flowers per plant. The opportunity for selection and strength of herbivore-mediated selection on number of flowers varied nonlinearly with the intensity of herbivory among populations. These parameters increased and then decreased with increasing intensity of plant-herbivore interactions, defined as an increase in the ratio of herbivore-damaged flowers per individual. Our results provide novel insights into how plant-antagonistic interactions can shape spatial variation in selection on floral traits and contribute toward understanding the mechanistic basis of geographic variation in angiosperm flowers.
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Affiliation(s)
- Yun Wu
- School of Civil Engineering, Architecture and Environment, Xihua University, Chengdu, China
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, School of Ecology and Environmental Science, Yunnan University, Kunming, China
| | - Spencer C. H. Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Xuyu Duan
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, China
| | - Jie Zhang
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, School of Ecology and Environmental Science, Yunnan University, Kunming, China
| | - Yongpeng Cha
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, School of Ecology and Environmental Science, Yunnan University, Kunming, China
| | - Chengyi Tu
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, School of Ecology and Environmental Science, Yunnan University, Kunming, China
| | - Qingjun Li
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, School of Ecology and Environmental Science, Yunnan University, Kunming, China
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Kulbaba MW, Shaw RG. Lifetime Fitness through Female and Male Function: Influences of Genetically Effective Population Size and Density. Am Nat 2021; 197:434-447. [PMID: 33755534 DOI: 10.1086/713067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractAn individual's lifetime fitness and patterns of mating between individuals are interdependent features of sexual organisms. Mating systems (outcrossing vs. selfing or mating between close relatives) can affect the distribution of offspring fitness, which generally declines with inbreeding, which in turn is related to a population's genetically effective size (Ne). Fitness and mating patterns are also expected to vary with proximity of mates (i.e., population density). Consequently, density and Ne may influence demographic and genetic changes over generations and interact in their effects. Here, we report an experiment designed to assess the influence of these two population-level properties on mating system and lifetime fitness. In experimental arrays under quasi-natural conditions, we varied the density and Ne of the hermaphroditic annual legume Chamaecrista fasciculata. We recorded components of fitness for each individual and employed microsatellite markers to estimate outcrossing and assign paternity. We used aster analyses to estimate lifetime fitness for genetic families using female (seeds set) and male (seeds sired) reproduction as fitness measures. With estimates from these analyses, we assessed the evidence for a trade-off between fitness attained through female versus male function, but we found none. Lifetime fitness increased with density, especially under high Ne. Outcrossing rates increased with density under high Ne but declined modestly with density under low Ne. Our results show that density and Ne have strong direct effects on fitness and mating systems, with negative fitness effects of low Ne limiting the positive effects of increasing density. These findings highlight the importance of the interactive effects of density and Ne on lifetime fitness.
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12
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Cao HP, He YT, Zhong L, Wang XJ, Barrett SCH, Wang H, Li DZ, Zhou W. Characterization of 30 microsatellite markers for distylous Primula denticulata (Primulaceae) using HiSeq sequencing. Genes Genet Syst 2020; 95:275-279. [PMID: 33328391 DOI: 10.1266/ggs.20-00003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Primula denticulata exhibits considerable variation in floral morphology and flowering phenology along elevational gradients in SW China. We isolated 30 microsatellite markers from P. denticulata to facilitate further investigation of population genetics and floral evolution in this species. We used the HiSeq X-Ten sequencing system to develop a set of markers, and measured polymorphism and genetic diversity in a sample of 72 individuals from three natural populations of P. denticulata subsp. denticulata. The markers displayed relatively high polymorphism, with the number of alleles ranging from two to seven (mean = 3.567). The observed and expected heterozygosity ranged from 0 to 1.000 and 0.041 to 0.702, respectively. Twenty-eight of the loci were also successfully amplified in P. denticulata subsp. sinodenticulata. The microsatellite markers we have identified will provide valuable tools for investigations of the population genetic structure, mating systems and phylogeography of the P. denticulata complex, and will help to address questions concerning the ecological and genetic mechanisms responsible for the evolution of reproductive traits in the species.
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Affiliation(s)
- Hao-Pu Cao
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences.,School of Life Science, Yunnan University
| | - Yu-Ting He
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences.,University of Chinese Academy of Sciences
| | - Li Zhong
- University of Chinese Academy of Sciences.,Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences
| | - Xin-Jia Wang
- University of Chinese Academy of Sciences.,Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences
| | | | - Hong Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences
| | - De-Zhu Li
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences
| | - Wei Zhou
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences
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Ganguly S, Barua D. High herkogamy but low reciprocity characterizes isoplethic populations of Jasminum malabaricum, a species with stigma-height dimorphism. PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:899-909. [PMID: 32352185 DOI: 10.1111/plb.13127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
Studies of floral polymorphisms have focused on heterostyly, while stigma-height dimorphism has received considerably less attention. Few studies have examined the reproductive biology of species with stigma-height dimorphism to understand how factors influencing mate availability and pollen transfer are related to morph ratios in populations. Floral morphological traits, especially herkogamy and reciprocity, pollinator visitation, breeding system and spatiotemporal mate availability, are known to affect inter-morph pollination and morph ratios in species with stigma-height dimorphism. In this study, we investigated the presence of stigma-height dimorphism and estimated morph ratios in four naturally occurring populations of Jasminum malabaricum. We quantified morph- and population-specific differences in the abovementioned factors in these populations to understand the observed morph ratios. The positions of anthers and stigmas were characteristic of stigma-height dimorphism, the first report of this polymorphism in the genus. All study populations were isoplethic, implying equal fitness of both morphs. Herkogamy was higher in the short-styled morph, while reciprocity was higher between the long-styled stigma and short-styled anthers. Long- and short-tongued pollinators were common floral visitors, and we observed no differences between morphs in spatiotemporal mate availability or pollinator visitation. Neither morph exhibited self- or heteromorphic incompatibility. The short-styled stigma had lower reciprocity but likely receives sufficient inter-morph pollen from long-tongued pollinators, and also by avoiding self-pollination due to higher herkogamy. These results highlight the importance of sufficient effective pollinators and floral morphological features, particularly herkogamy, in maintaining isoplethy in species with stigma-height dimorphism.
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Affiliation(s)
- S Ganguly
- Department of Biology, Indian Institute of Science Education and Research, Pune, India
| | - D Barua
- Department of Biology, Indian Institute of Science Education and Research, Pune, India
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14
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Zhou J, Reynolds RJ, Zimmer EA, Dudash MR, Fenster CB. Variable and sexually conflicting selection on
Silene stellata
floral traits by a putative moth pollinator selective agent. Evolution 2020; 74:1321-1334. [DOI: 10.1111/evo.13965] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 02/21/2020] [Accepted: 03/13/2020] [Indexed: 10/24/2022]
Affiliation(s)
- Juannan Zhou
- Simons Center for Quantitative Biology Cold Spring Harbor Laboratory Cold Spring Harbor NY 11724 USA
| | - Richard J. Reynolds
- Division of Clinical Immunology and Rheumatology, Department of Medicine University of Alabama at Birmingham Birmingham AL 35294 USA
| | - Elizabeth A. Zimmer
- Department of Botany National Museum of Natural History, MRC 166 Smithsonian Institution Washington DC 20013–7012 USA
| | - Michele R. Dudash
- Department of Natural Resource Management South Dakota State University Brookings SD 57007 USA
| | - Charles B. Fenster
- Department of Biology and Microbiology South Dakota State University Brookings SD 57007 USA
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15
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Zhao Z, Hou M, Wang Y, Du G. Phenological variation of flower longevity and duration of sex phases in a protandrous alpine plant: potential causes and fitness significance. BMC PLANT BIOLOGY 2020; 20:137. [PMID: 32245411 PMCID: PMC7118941 DOI: 10.1186/s12870-020-02356-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Flower longevity plays an important role in pollen dispersal and reproductive success in plants. In dichogamous plants, the duration of anthesis as well as the time allocated to male and female functions can vary in response to intrinsic factors (e.g., flowering time and resource allocation) and pollination context along a growth season. However, the fitness consequences of phenological dynamics have rarely been examined. This study aims to unravel the potential causes driving variation in flower longevity, duration of sex phases, and phenotypic sex during a flowering season of strongly protandrous Aconitum gymnandrum, and particularly reproductive consequences of the phenological pattern. RESULTS Population floral sex ratio shifted from completely male at the beginning to completely female at the end of the season, as is common in other protandrous plants. Phenological dynamics of the floral sex ratio and the duration of sex phases caused a shift from femaleness to maleness in the mean phenotypic sex over the whole season. Floral longevity was negatively correlated with flower size and positively affected by temperature. Early flowers within inflorescences rather than early-flowering individuals emphasized the duration of female over male phase. Owing to the dominance of male-phase flowers, early flowering for individual flowers and plants, or female-biased sex resulted in higher pollen deposition per flower and seed set. At the flower level, flower longevity positively affected female reproductive success, while the effect of flower size was negative. By contrast, plant-level female reproductive success was negatively affected by flower longevity but positively correlated to flower size. CONCLUSIONS The major result of this study lies in elucidating the relationship between variation in phenological sex expression and floral longevity and their fitness consequences of protandrous A. gymnandrum. The contrasting results on female fitness for individual flowers and plants contribute to our current understanding of the adaptive significance of floral longevity.
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Affiliation(s)
- Zhigang Zhao
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000 China
| | - Meng Hou
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000 China
| | - Yijie Wang
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000 China
| | - Guozhen Du
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000 China
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16
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Chen ZQ, Zhou ZL, Wang LL, Meng LH, Duan YW. Development of Microsatellite Markers for a Dioecious Herpetospermum pedunculosum (Cucurbitaceae). Evol Bioinform Online 2020; 16:1176934320908261. [PMID: 32127748 PMCID: PMC7036485 DOI: 10.1177/1176934320908261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 01/24/2020] [Indexed: 11/16/2022] Open
Abstract
Understanding the evolution of flower diversity is a central topic in plant evolutionary ecology, and natural selection on floral traits via male fitness could be estimated quantitatively using microsatellites. Here, based on RNA sequencing, we developed simple sequence repeat primers and verified polymorphisms in 2 wild populations of Herpetospermum pedunculosum (Cucurbitaceae), a dioecious annual plants native to the Himalaya Mountains. A total of 131 paired primers were designed; 15 paired primers were found to be polymorphic, with the expected heterozygosity varying between 0.280 and 0.767. We also identified 58 genotypes in 20 plants from the 2 populations. Conclusively, these primers could be effective in examining male fitness and population genetic structure of H pedunculosum in future studies.
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Affiliation(s)
- Zhu-Qing Chen
- School of Life Sciences, Key Laboratory
of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan Normal
University, Kunming, P.R. China
| | - Zhi-Li Zhou
- The Germplasm Bank of Wild Species,
Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, P.R. China
| | - Lin-Lin Wang
- The Germplasm Bank of Wild Species,
Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, P.R. China
| | - Li-Hua Meng
- School of Life Sciences, Key Laboratory
of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan Normal
University, Kunming, P.R. China
| | - Yuan-Wen Duan
- The Germplasm Bank of Wild Species,
Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, P.R. China
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17
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Teixido AL, Aizen MA. Reproductive assurance weakens pollinator-mediated selection on flower size in an annual mixed-mating species. ANNALS OF BOTANY 2019; 123:1067-1077. [PMID: 30778517 PMCID: PMC6589515 DOI: 10.1093/aob/mcz014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 01/14/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND AND AIMS In animal-pollinated plants, direct and indirect selection for large and small flowers in predominantly outcrossing and selfing species, respectively, is a common consequence of pollen limitation (PL). However, many hermaphroditic species show a mixed-mating system known as delayed selfing, which provides reproductive assurance (RA) only when outcrossing is not realized. Although RA is expected to reduce pollinator-mediated selection towards larger flowers, the consequences of delayed selfing for selection on flower size in mixed-mating species remain overlooked. We investigated whether RA weakens selection on flower size in Tuberaria guttata, a mixed-mating annual herb. METHODS We related pollinator visitation rates to flower size and measured seed production in emasculated, hand cross-pollinated and intact (control) flowers in three natural populations. For each population, we estimated variation in PL and RA across individuals differing in flower size and phenotypic selection on this trait. KEY RESULTS Pollinator visitation increased and RA decreased with flower size in all populations. Increasing RA diminished but did not fully alleviate PL, because of early-acting inbreeding depression. In the least-visited and most pollen-limited population, RA increased seed production by >200 %, intensely counteracting the strong pollinator-mediated selection for larger corollas. In the most-visited population, however, RA increased seed production by an average of only 9 %. This population exhibited the largest fraction of individuals that showed a decrease in seed production due to selfing and the weakest pollinator-mediated selection on flower size. CONCLUSIONS The results suggest that the balance between the extent of RA and outcrossing contributes to determine flower size in mixed-mating systems. Pollinator-mediated selection favours larger flowers by increasing outcrossed seeds, but the benefits of RA greatly lessen this effect, especially under severe conditions of pollen limitation. Our findings also indicate that a mixed-mating system can represent an 'evolutionary trap' under an adequate pollinator supply.
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Affiliation(s)
- Alberto L Teixido
- Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Madrid, Spain
| | - Marcelo A Aizen
- Grupo de Ecología de la Polinización, Universidad Nacional del Comahue and INIBIOMA-CONICET, Río Negro, Argentina
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18
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Wu Y, Zhong T, Liu GL, Tan LW, Li QJ. The relative strength of different floral visitors driving floral evolution within a Primula secundiflora population. Evol Ecol 2018. [DOI: 10.1007/s10682-018-9962-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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19
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Olito C, Abbott JK, Jordan CY. The interaction between sex-specific selection and local adaptation in species without separate sexes. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170426. [PMID: 30150224 PMCID: PMC6125720 DOI: 10.1098/rstb.2017.0426] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2018] [Indexed: 11/12/2022] Open
Abstract
Local adaptation in hermaphrodite species can be based on a variety of fitness components, including survival, as well as both female and male sex-functions within individuals. When selection via female and male fitness components varies spatially (e.g. due to environmental heterogeneity), local adaptation will depend, in part, on variation in selection through each fitness component, and the extent to which genetic trade-offs between sex-functions maintain genetic variation necessary for adaptation. Local adaptation will also depend on the hermaphrodite mating system because self-fertilization alters several key factors influencing selection and the maintenance of genetic variance underlying trade-offs between the sex-functions (sexually antagonistic polymorphism). As a first step to guide intuition regarding sex-specific adaptation in hermaphrodites, we develop a simple theoretical model incorporating the essential features of hermaphrodite mating and adaptation in a spatially heterogeneous environment, and explore the interaction between sex-specific selection, self-fertilization and local adaptation. Our results suggest that opportunities for sex-specific local adaptation in hermaphrodites depend strongly on the extent of self-fertilization and inbreeding depression. Using our model as a conceptual framework, we provide a broad overview of the literature on sex-specific selection and local adaptation in hermaphroditic plants and animals, emphasizing promising future directions in light of our theoretical predictions.This article is part of the theme issue 'Linking local adaptation with the evolution of sex differences'.
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Affiliation(s)
- Colin Olito
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Victoria 3800, Australia
- Department of Biology, Section for Evolutionary Ecology, Lund University, Lund, Sweden
| | - Jessica K Abbott
- Department of Biology, Section for Evolutionary Ecology, Lund University, Lund, Sweden
| | - Crispin Y Jordan
- School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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20
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Oddou-Muratorio S, Gauzere J, Bontemps A, Rey JF, Klein EK. Tree, sex and size: Ecological determinants of male vs. female fecundity in three Fagus sylvatica
stands. Mol Ecol 2018; 27:3131-3145. [DOI: 10.1111/mec.14770] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 05/29/2018] [Accepted: 06/07/2018] [Indexed: 12/25/2022]
Affiliation(s)
| | - Julie Gauzere
- URFM; INRA; Avignon France
- BioSP; INRA; Avignon France
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21
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Wu Y, Li QJ. Phenotypic selection on flowering phenology and pollination efficiency traits between Primula populations with different pollinator assemblages. Ecol Evol 2017; 7:7599-7608. [PMID: 29043017 PMCID: PMC5632619 DOI: 10.1002/ece3.3258] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/13/2017] [Accepted: 06/28/2017] [Indexed: 12/12/2022] Open
Abstract
Floral traits have largely been attributed to phenotypic selection in plant–pollinator interactions. However, the strength of this link has rarely been ascertained with real pollinators. We conducted pollinator observations and estimated selection through female fitness on flowering phenology and floral traits between two Primula secundiflora populations. We quantified pollinator‐mediated selection by subtracting estimates of selection gradients of plants receiving supplemental hand pollination from those of plants receiving open pollination. There was net directional selection for an earlier flowering start date at populations where the dominant pollinators were syrphid flies, and flowering phenology was also subjected to stabilized quadratic selection. However, a later flowering start date was significantly selected at populations where the dominant pollinators were legitimate (normal pollination through the corolla tube entrance) and illegitimate bumblebees (abnormal pollination through nectar robbing hole which located at the corolla tube), and flowering phenology was subjected to disruptive quadratic selection. Wider corolla tube entrance diameter was selected at both populations. Furthermore, the strength of net directional selection on flowering start date and corolla tube entrance diameter was stronger at the population where the dominant pollinators were syrphid flies. Pollinator‐mediated selection explained most of the between‐population variations in the net directional selection on flowering phenology and corolla tube entrance diameter. Our results suggested the important influence of pollinator‐mediated selection on floral evolution. Variations in pollinator assemblages not only resulted in variation in the direction of selection but also the strength of selection on floral traits.
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Affiliation(s)
- Yun Wu
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Menglun, Mengla County China.,University of Chinese Academy of Sciences Beijing China
| | - Qing-Jun Li
- Laboratory of Ecology and Evolutionary Biology State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University Kunming China
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22
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Trunschke J, Sletvold N, Ågren J. Interaction intensity and pollinator-mediated selection. THE NEW PHYTOLOGIST 2017; 214:1381-1389. [PMID: 28240377 DOI: 10.1111/nph.14479] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/15/2017] [Indexed: 05/26/2023]
Abstract
In animal-pollinated plants, the opportunity for selection and the strength of pollinator-mediated selection are expected to increase with the degree of pollen limitation. However, whether differences in pollen limitation can explain variation in pollinator-mediated and net selection among animal-pollinated species is poorly understood. In the present study, we quantified pollen limitation, variance in relative fitness and pollinator-mediated selection on five traits important for pollinator attraction (flowering start, plant height, flower number, flower size) and pollination efficiency (spur length) in natural populations of 12 orchid species. Pollinator-mediated selection was quantified by subtracting estimates of selection gradients for plants receiving supplemental hand-pollination from estimates obtained for open-pollinated control plants. Mean pollen limitation ranged from zero to 0.96. Opportunity for selection, pollinator-mediated selection and net selection were all positively related to pollen limitation, whereas nonpollinator-mediated selection was not. Opportunity for selection varied five-fold, strength of pollinator-mediated selection varied three-fold and net selection varied 1.5-fold among species. Supplemental hand-pollination reduced both opportunity for selection and selection on floral traits. The results show that the intensity of biotic interactions is an important determinant of the selection regime, and indicate that the potential for pollinator-mediated selection and divergence in floral traits is particularly high in species that are strongly pollen-limited.
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Affiliation(s)
- Judith Trunschke
- Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18 D, Uppsala, SE-752 36, Sweden
| | - Nina Sletvold
- Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18 D, Uppsala, SE-752 36, Sweden
| | - Jon Ågren
- Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18 D, Uppsala, SE-752 36, Sweden
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23
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Dorken ME, Perry LE. Correlated paternity measures mate monopolization and scales with the magnitude of sexual selection. J Evol Biol 2016; 30:377-387. [DOI: 10.1111/jeb.13013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 11/03/2016] [Accepted: 11/09/2016] [Indexed: 01/03/2023]
Affiliation(s)
- M. E. Dorken
- Department of Biology; Trent University; Peterborough ON Canada
| | - L. E. Perry
- Department of Biology; Trent University; Peterborough ON Canada
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24
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Austen EJ, Weis AE. Estimating selection through male fitness: three complementary methods illuminate the nature and causes of selection on flowering time. Proc Biol Sci 2016; 283:20152635. [PMID: 26911957 DOI: 10.1098/rspb.2015.2635] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Our understanding of selection through male fitness is limited by the resource demands and indirect nature of the best available genetic techniques. Applying complementary, independent approaches to this problem can help clarify evolution through male function. We applied three methods to estimate selection on flowering time through male fitness in experimental populations of the annual plant Brassica rapa: (i) an analysis of mating opportunity based on flower production schedules, (ii) genetic paternity analysis, and (iii) a novel approach based on principles of experimental evolution. Selection differentials estimated by the first method disagreed with those estimated by the other two, indicating that mating opportunity was not the principal driver of selection on flowering time. The genetic and experimental evolution methods exhibited striking agreement overall, but a slight discrepancy between the two suggested that negative environmental covariance between age at flowering and male fitness may have contributed to phenotypic selection. Together, the three methods enriched our understanding of selection on flowering time, from mating opportunity to phenotypic selection to evolutionary response. The novel experimental evolution method may provide a means of examining selection through male fitness when genetic paternity analysis is not possible.
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Affiliation(s)
- Emily J Austen
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2 Department of Biology, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5
| | - Arthur E Weis
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
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25
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Austen EJ, Weis AE. The causes of selection on flowering time through male fitness in a hermaphroditic annual plant. Evolution 2015; 70:111-25. [PMID: 26596860 DOI: 10.1111/evo.12823] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 10/14/2015] [Accepted: 11/11/2015] [Indexed: 12/18/2022]
Abstract
Flowering is a key life-history event whose timing almost certainly affects both male and female fitness, but tests of selection on flowering time through male fitness are few. Such selection may arise from direct effects of flowering time, and indirect effects through covariance between flowering time and the environment experienced during reproduction. To isolate these intrinsically correlated associations, we staggered planting dates of Brassica rapa families with known flowering times, creating populations in which age at flowering (i.e., flowering time genotype) and Julian date of flowering (i.e., flowering time environment) were positively, negatively, or uncorrelated. Genetic paternity analysis revealed that male fitness was not strongly influenced by seasonal environmental changes. Instead, when age and date were uncorrelated, selection through male fitness strongly favored young age at flowering. Strategic sampling offspring for paternity analysis rejected covariance between sire age at flowering and dam quality as the cause of this selection. Results instead suggest a negative association between age at flowering and pollen competitive ability. The manipulation also revealed that, at least in B. rapa, the often-observed correlation between flowering time and flowering duration is environmental, not genetic, in origin.
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Affiliation(s)
- Emily J Austen
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada, M5S 3B2. .,Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 6N5.
| | - Arthur E Weis
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada, M5S 3B2
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26
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Chapurlat E, Ågren J, Sletvold N. Spatial variation in pollinator-mediated selection on phenology, floral display and spur length in the orchid Gymnadenia conopsea. THE NEW PHYTOLOGIST 2015; 208:1264-1275. [PMID: 26183369 DOI: 10.1111/nph.13555] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 06/09/2015] [Indexed: 06/04/2023]
Abstract
Spatial variation in plant-pollinator interactions may cause variation in pollinator-mediated selection on floral traits, but to establish this link conclusively experimental studies are needed. We quantified pollinator-mediated selection on flowering phenology and morphology in four populations of the fragrant orchid Gymnadenia conopsea, and compared selection mediated by diurnal and nocturnal pollinators in two of the populations. Variation in pollinator-mediated selection explained most of the among-population variation in the strength of directional and correlational selection. Pollinators mediated correlational selection on pairs of display traits, and on one display trait and spur length, a trait affecting pollination efficiency. Only nocturnal pollinators selected for longer spurs, and mediated stronger selection on the number of flowers compared with diurnal pollinators in one population. The two types of pollinators caused correlational selection on different pairs of traits and selected for different combinations of spur length and number of flowers. The results demonstrate that spatial variation in interactions with pollinators may result in differences in directional and correlational selection on floral traits in a plant with a semi-generalized pollination system, and suggest that differences in the relative importance of diurnal and nocturnal pollinators can cause variation in selection.
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Affiliation(s)
- Elodie Chapurlat
- Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36, Uppsala, Sweden
| | - Jon Ågren
- Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36, Uppsala, Sweden
| | - Nina Sletvold
- Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36, Uppsala, Sweden
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27
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Jordan CY, Connallon T. Sexually antagonistic polymorphism in simultaneous hermaphrodites. Evolution 2014; 68:3555-69. [PMID: 25311368 DOI: 10.1111/evo.12536] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/09/2014] [Indexed: 12/22/2022]
Abstract
In hermaphrodites, pleiotropic genetic trade-offs between female and male reproductive functions can lead to sexually antagonistic (SA) selection, where individual alleles have conflicting fitness effects on each sex function. Although an extensive theory of SA selection exists for dioecious species, these results have not been generalized to hermaphrodites. We develop population genetic models of SA selection in simultaneous hermaphrodites, and evaluate effects of dominance, selection on each sex function, self-fertilization, and population size on the maintenance of polymorphism. Under obligate outcrossing, hermaphrodite model predictions converge exactly with those of dioecious populations. Self-fertilization in hermaphrodites generates three points of divergence with dioecious theory. First, opportunities for stable polymorphism decline sharply and become less sensitive to dominance with increased selfing. Second, selfing introduces an asymmetry in the relative importance of selection through male versus female reproductive functions, expands the parameter space favorable for the evolutionary invasion of female-beneficial alleles, and restricts invasion criteria for male-beneficial alleles. Finally, contrary to models of unconditionally beneficial alleles, selfing decreases genetic hitchhiking effects of invading SA alleles, and should therefore decrease these population genetic signals of SA polymorphisms. We discuss implications of SA selection in hermaphrodites, including its potential role in the evolution of "selfing syndromes."
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Affiliation(s)
- Crispin Y Jordan
- Ashworth Laboratories, Institute of Evolutionary Biology, The University of Edinburgh, Kings Buildings, West Mains Road, Edinburgh, EH9 3JT, United Kingdom.
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28
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Pérez-Barrales R, Simón-Porcar VI, Santos-Gally R, Arroyo J. Phenotypic integration in style dimorphic daffodils (Narcissus, Amaryllidaceae) with different pollinators. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130258. [PMID: 25002703 PMCID: PMC4084543 DOI: 10.1098/rstb.2013.0258] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Different pollinators can exert different selective pressures on floral traits, depending on how they fit with flowers, which should be reflected in the patterns of variation and covariation of traits. Surprisingly, empirical evidence in support of this view is scarce. Here, we have studied whether the variation observed in floral phenotypic integration and covariation of traits in Narcissus species is associated with different groups of pollinators. Phenotypic integration was studied in two style dimorphic species, both with dimorphic populations mostly visited by long-tongued pollinators (close fit with flowers), and monomorphic populations visited by short-tongued insects (loose fit). For N. papyraceus, the patterns of variation and correlation among traits involved in different functions (attraction and fit with pollinators, transfer of pollen) were compared within and between population types. The genetic diversity of populations was also studied to control for possible effects on phenotypic variation. In both species, populations with long-tongued pollinators displayed greater phenotypic integration than those with short-tongued pollinators. Also, the correlations among traits involved in the same function were stronger than across functions. Furthermore, traits involved in the transfer of pollen were consistently more correlated and less variable than traits involved in the attraction of insects, and these differences were larger in dimorphic than monomorphic populations. In addition, population genetic parameters did not correlate with phenotypic integration or variation. Altogether, our results support current views of the role of pollinators in the evolution of floral integration.
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Affiliation(s)
- Rocío Pérez-Barrales
- School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK Departmento de Biología Vegetal y Ecología, University of Seville, Seville 41080, Spain
| | | | - Rocío Santos-Gally
- Departmento de Biología Vegetal y Ecología, University of Seville, Seville 41080, Spain
| | - Juan Arroyo
- Departmento de Biología Vegetal y Ecología, University of Seville, Seville 41080, Spain
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Stabilizing selection on nectar concentration in wild Petunia axillaris, as revealed by genetic analysis of pollen dispersal. Evol Ecol 2014. [DOI: 10.1007/s10682-014-9714-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Hirota SK, Nitta K, Suyama Y, Kawakubo N, Yasumoto AA, Yahara T. Pollinator-mediated selection on flower color, flower scent and flower morphology of Hemerocallis: evidence from genotyping individual pollen grains on the stigma. PLoS One 2013; 8:e85601. [PMID: 24376890 PMCID: PMC3871637 DOI: 10.1371/journal.pone.0085601] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 11/29/2013] [Indexed: 11/18/2022] Open
Abstract
To trace the fate of individual pollen grains through pollination processes, we determined genotypes of single pollen grains deposited on Hemerocallis stigmas in an experimental mixed-species array. Hemerocallis fulva, pollinated by butterflies, has diurnal, reddish and unscented flowers, and H. citrina, pollinated by hawkmoths, has nocturnal, yellowish and sweet scent flowers. We observed pollinator visits to an experimental array of 24 H. fulva and 12 F2 hybrids between the two species (H. fulva and H. citrina) and collected stigmas after every trip bout of swallowtail butterflies or hawkmoths. We then measured selection by swallowtail butterflies or hawkmoths through male and female components of pollination success as determined by single pollen genotyping. As expected, swallowtail butterflies imposed selection on reddish color and weak scent: the number of outcross pollen grains acquired is a quadratic function of flower color with the maximum at reddish color, and the combined pollination success was maximal at weak scent (almost unrecognizable for human). This explains why H. fulva, with reddish flowers and no recognizable scent, is mainly pollinated by swallowtail butterflies. However, we found no evidence of hawkmoths-mediated selection on flower color or scent. Our findings do not support a hypothesis that yellow flower color and strong scent intensity, the distinctive floral characteristics of H. citrina, having evolved in adaptations to hawkmoths. We suggest that the key trait that triggers the evolution of nocturnal flowers is flowering time rather than flower color and scent.
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Affiliation(s)
- Shun K. Hirota
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Kozue Nitta
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Yoshihisa Suyama
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan
| | - Nobumitsu Kawakubo
- Department of Environmental Science, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Akiko A. Yasumoto
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Tetsukazu Yahara
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan
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31
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Sletvold N, Grindeland JM, Agren J. Vegetation context influences the strength and targets of pollinator-mediated selection in a deceptive orchid. Ecology 2013; 94:1236-42. [PMID: 23923483 DOI: 10.1890/12-1840.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Clarifying the relationship between environmental context and the adaptive significance of floral traits is fundamental for an understanding of spatial and temporal variation in pollinator-mediated selection. We manipulated vegetation height and pollination regime of the orchid Dactylorhiza lapponica in a factorial design to test whether pollinator-mediated selection on floral traits is stronger in tall than in short vegetation, and whether this difference is larger for visual traits affecting pollinator attraction than for traits affecting pollination efficiency. In tall vegetation, pollinators mediated strong selection for taller plants (change in selection gradient for pollination, deltabeta(poll) = 0.33), more flowers (deltabeta(poll) = 0.34), and longer spurs (deltabeta(poll) = 0.42). In short vegetation, there was no significant selection on plant height, and pollinator-mediated selection on number of flowers and spur length was reduced by 52% and 25%, respectively. The results demonstrate experimentally that vegetation context can markedly influence the strength of pollinator-mediated selection on visual display traits, and indicate that this effect is weaker for traits affecting pollination efficiency. The study illustrates how crossed manipulations of environmental factors can reveal the causal links between ecological context and selection on floral traits.
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Affiliation(s)
- Nina Sletvold
- Department of Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18 D, SE-752 36 Uppsala, Sweden.
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32
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Pélabon C, Osler NC, Diekmann M, Graae BJ. Decoupled phenotypic variation between floral and vegetative traits: distinguishing between developmental and environmental correlations. ANNALS OF BOTANY 2013; 111:935-44. [PMID: 23471008 PMCID: PMC3631334 DOI: 10.1093/aob/mct050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS In species with specialized pollination, floral traits are expected to be relatively invariant and decoupled from the phenotypic variation affecting vegetative traits. However, inferring the degree of decoupling between morphological characters from patterns of phenotypic correlations is difficult because phenotypic correlations result from the superimposition of several sources of covariance. In this study it is hypothesized that, in some cases, negative environmental correlations generated by non-congruent reaction norms across traits overshadow positive developmental correlations and generate a decoupling of the phenotypic variation between vegetative and floral traits. METHODS To test this hypothesis, Campanula rotundifolia were grown from two distinct populations under two temperature treatments, and patterns of correlation were analysed between leaf size and flower size within and among treatments. KEY RESULTS Flower size was less sensitive to temperature variation than leaf size. Furthermore, flower size and leaf size showed temperature-induced reaction norms in opposite directions. Flower size decreased with an increasing temperature, while leaf size increased. Consequently, among treatments, correlations between leaf size and flower size were negative or absent, while, within treatments, these correlations were positive or absent in the cold and warm environments, respectively. CONCLUSIONS These results confirm that the decoupling of the phenotypic variation between vegetative and floral traits can be dependent on the environment. They also underline the importance of distinguishing sources of phenotypic covariance when testing hypotheses about phenotypic integration.
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Affiliation(s)
- Christophe Pélabon
- Centre for Conservation Biology, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
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33
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Large and abundant flowers increase indirect costs of corollas: a study of coflowering sympatric Mediterranean species of contrasting flower size. Oecologia 2013; 173:73-81. [PMID: 23404071 DOI: 10.1007/s00442-013-2609-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 01/29/2013] [Indexed: 10/27/2022]
Abstract
Large floral displays receive more pollinator visits but involve higher production and maintenance costs. This can result in indirect costs which may negatively affect functions like reproductive output. In this study, we explored the relationship between floral display and indirect costs in two pairs of coflowering sympatric Mediterranean Cistus of contrasting flower size. We hypothesized that: (1) corolla production entails direct costs in dry mass, N and P, (2) corollas entail significant indirect costs in terms of fruit set and seed production, (3) indirect costs increase with floral display, (4) indirect costs are greater in larger-flowered sympatric species, and (5) local climatic conditions influence indirect costs. We compared fruit set and seed production of petal-removed flowers and unmanipulated control flowers and evaluated the influence of mean flower number and mean flower size on relative fruit and seed gain of petal-removed and control flowers. Fruit set and seed production were significantly higher in petal-removed flowers in all the studied species. A positive relationship was found between relative fruit gain and mean individual flower size within species. In one pair of species, fruit gain was higher in the large-flowered species, as was the correlation between fruit gain and mean number of open flowers. In the other pair, the correlation between fruit gain and mean flower size was also higher in the large-flowered species. These results reveal that Mediterranean environments impose significant constraints on floral display, counteracting advantages of large flowers from the pollination point of view with increased indirect costs of such flowers.
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34
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35
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Kulbaba MW, Worley AC. Selection on floral design in Polemonium brandegeei (Polemoniaceae): female and male fitness under hawkmoth pollination. Evolution 2012; 66:1344-59. [PMID: 22519776 DOI: 10.1111/j.1558-5646.2011.01536.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Plant-pollinator interactions promote the evolution of floral traits that attract pollinators and facilitate efficient pollen transfer. The spatial separation of sex organs, herkogamy, is believed to limit sexual interference in hermaphrodite flowers. Reverse herkogamy (stigma recessed below anthers) and long, narrow corolla tubes are expected to promote efficiency in male function under hawkmoth pollination. We tested this prediction by measuring selection in six experimental arrays of Polemonium brandegeei, a species that displays continuous variation in herkogamy, resulting in a range of recessed to exserted stigmas. Under glasshouse conditions, we measured pollen removal and deposition, and estimated selection gradients (β) through female fitness (seeds set) and male fitness (siring success based on six polymorphic microsatellite loci). Siring success was higher in plants with more nectar sugar and narrow corolla tubes. However, selection through female function for reverse herkogamy was considerably stronger than was selection through male function. Hawkmoths were initially attracted to larger flowers, but overall preferred plants with reverse herkogamy. Greater pollen deposition and seed set also occurred in reverse herkogamous plants. Thus, reverse herkogamy may be maintained by hawkmoths through female rather than male function. Further, our results suggest that pollinator attraction may play a considerable role in enhancing female function.
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Affiliation(s)
- Mason W Kulbaba
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
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36
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Artz DR, Hsu CL, Nault BA. Influence of honey bee, Apis mellifera, hives and field size on foraging activity of native bee species in pumpkin fields. ENVIRONMENTAL ENTOMOLOGY 2011; 40:1144-1158. [PMID: 22251726 DOI: 10.1603/en10218] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The purpose of this study was to identify bee species active in pumpkin fields in New York and to estimate their potential as pollinators by examining their foraging activity. In addition, we examined whether foraging activity was affected by either the addition of hives of the honey bee, Apis mellifera L., or by field size. Thirty-five pumpkin (Cucurbita spp.) fields ranging from 0.6 to 26.3 ha, 12 supplemented with A. mellifera hives and 23 not supplemented, were sampled during peak flowering over three successive weeks in 2008 and 2009. Flowers from 300 plants per field were visually sampled for bees on each sampling date. A. mellifera, Bombus impatiens Cresson, and Peponapis pruinosa (Say) accounted for 99% of all bee visits to flowers. A. mellifera and B. impatiens visited significantly more pistillate flowers than would be expected by chance, whereas P. pruinosa showed no preference for visiting pistillate flowers. There were significantly more A. mellifera visits per flower in fields supplemented with A. mellifera hives than in fields not supplemented, but there were significantly fewer P. pruinosa visits in supplemented fields. The number of B. impatiens visits was not affected by supplementation, but was affected by number of flowers per field. A. mellifera and P. pruinosa visits were not affected by field size, but B. impatiens visited fewer flowers as field size increased in fields that were not supplemented with A. mellifera hives. Declining A. mellifera populations may increase the relative importance of B. impatiens in pollinating pumpkins in New York.
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Affiliation(s)
- Derek R Artz
- Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, USA.
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Anthes N, David P, Auld JR, Hoffer JNA, Jarne P, Koene JM, Kokko H, Lorenzi MC, Pélissié B, Sprenger D, Staikou A, Schärer L. Bateman gradients in hermaphrodites: an extended approach to quantify sexual selection. Am Nat 2010; 176:249-63. [PMID: 20636132 DOI: 10.1086/655218] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Sexual selection is often quantified using Bateman gradients, which represent sex-specific regression slopes of reproductive success on mating success and thus describe the expected fitness returns from mating more often. Although the analytical framework for Bateman gradients aimed at covering all sexual systems, empirical studies are biased toward separate-sex organisms, probably because important characteristics of other systems remain incompletely treated. Our synthesis complements the existing Bateman gradient approach with three essential reproductive features of simultaneous hermaphrodites. First, mating in one sex may affect fitness via the opposite sex, for example, through energetic trade-offs. We integrate cross-sex selection effects and show how they help characterizing sexually mutualistic versus antagonistic selection. Second, male and female mating successes may be correlated, complicating the interpretation of Bateman gradients. We show how to quantify the impact of this correlation on sexual selection and propose a principal component analysis on male and female mating success to facilitate interpretation. Third, self-fertilization is accounted for by adding selfed progeny as a separate category of reproductive success to analyses of Bateman gradients. Finally, using a worked example from the snail Biomphalaria glabrata, we illustrate how the extended analytical framework can enhance our understanding of sexual selection in hermaphroditic animals and plants.
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Affiliation(s)
- Nils Anthes
- Institute for Evolution and Ecology, University of Tübingen, Germany.
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Rymer PD, Johnson SD, Savolainen V. Pollinator behaviour and plant speciation: can assortative mating and disruptive selection maintain distinct floral morphs in sympatry? THE NEW PHYTOLOGIST 2010; 188:426-436. [PMID: 20738786 DOI: 10.1111/j.1469-8137.2010.03438.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
• Pollinators, as gene flow vectors and selection agents, play a central role in the origin and maintenance of floral variation in natural populations. However, it is debatable whether pollination alone can complete the speciation process in sympatry. • Mating patterns and phenotypic selection on floral traits were characterized over two flowering seasons for sympatric corolla tube length morphs of the hawkmoth-pollinated iris Gladiolus longicollis. A mating model with genetic and spatial-temporal predictors was developed to identify seed paternity. A multivariate analysis was used to estimate selection on correlated floral traits based on maternal and paternal fitness. • Mating patterns among floral morphs were density dependent, resulting in assortative mating at low plant densities, and random mating among morphs at high densities. Weak disruptive selection on tube length was detected in one season for maternal fitness. Plant height was under opposing directional selection for maternal (+) and paternal (-) fitness functions. • These results indicate that G. longicollis morphs will introgress rather than diverge towards speciation. The lack of strong assortative mating, particularly at high densities, is predicted to result in the loss of rare morphs within populations, and indicates that spatial and temporal co-occurrences of floral morphs are evolutionarily unstable.
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Floral genetic architecture: an examination of QTL architecture underlying floral (co)variation across environments. Genetics 2010; 186:1451-65. [PMID: 20837996 DOI: 10.1534/genetics.110.119982] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genetic correlations are expected to be high among functionally related traits and lower between groups of traits with distinct functions (e.g., reproductive vs. resource-acquisition traits). Here, we explore the quantitative-genetic and QTL architecture of floral organ sizes, vegetative traits, and life history in a set of Brassica rapa recombinant inbred lines within and across field and greenhouse environments. Floral organ lengths were strongly positively correlated within both environments, and analysis of standardized G-matrices indicates that the structure of genetic correlations is ∼80% conserved across environments. Consistent with these correlations, we detected a total of 19 and 21 additive-effect floral QTL in the field and the greenhouse, respectively, and individual QTL typically affected multiple organ types. Interestingly, QTL×QTL epistasis also appeared to contribute to observed genetic correlations; i.e., interactions between two QTL had similar effects on filament length and two estimates of petal size. Although floral and nonfloral traits are hypothesized to be genetically decoupled, correlations between floral organ size and both vegetative and life-history traits were highly significant in the greenhouse; G-matrices of floral and vegetative traits as well as floral and life-history traits differed across environments. Correspondingly, many QTL (45% of those mapped in the greenhouse) showed environmental interactions, including approximately even numbers of floral and nonfloral QTL. Most instances of QTL×QTL epistasis for floral traits were environment dependent.
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40
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Pélabon C, Armbruster WS, Hansen TF. Experimental evidence for the Berg hypothesis: vegetative traits are more sensitive than pollination traits to environmental variation. Funct Ecol 2010. [DOI: 10.1111/j.1365-2435.2010.01770.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Christophe Pélabon
- Department of Biology, Centre for Conservation Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - W. Scott Armbruster
- Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
- School of Biological Sciences, King Henry Building, University of Portsmouth, Portsmouth PO1 2DY, UK
- Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska 99775, USA
| | - Thomas F. Hansen
- Department of Biology, Centre for Ecological and Evolutionary Synthesis, University of Oslo, 0316 Oslo, Norway
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41
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Alcántara JM, Bastida JM, Rey PJ. Linking divergent selection on vegetative traits to environmental variation and phenotypic diversification in the Iberian columbines (Aquilegia). J Evol Biol 2010; 23:1218-33. [PMID: 20406347 DOI: 10.1111/j.1420-9101.2010.01981.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Divergent selection is a key in the ecological theory of adaptive radiation. Most evidence on its causes and consequences relies on studies of pairs of populations or closely related taxa. However, adaptive radiation involves multiple taxa adapted to different environmental factors. We propose an operational definition of divergent selection to explore the continuum between divergent and convergent selection in multiple populations and taxa, and its links with environmental variation and phenotypic and taxonomic differentiation. We apply this approach to explore phenotypic differentiation of vegetative traits between 15 populations of four taxa of Iberian columbines (Gen. Aquilegia). Differences in soil rockiness impose divergent selection on inflorescence height and the number of flowers per inflorescence, likely affecting the processes of phenotypic and, in the case of inflorescence height, taxonomic diversification between taxa. Elevational variation imposes divergent selection on the number of leaves; however, the current pattern of divergent selection on this trait seems related to ecotypic differentiation within taxa but not to their taxonomic diversification.
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Affiliation(s)
- Julio M Alcántara
- Depto. Biología Animal, Biología Vegetal y Ecología, University of Jaén, Jaén, Spain.
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42
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Abstract
Flowering plants display spectacular floral diversity and a bewildering array of reproductive adaptations that promote mating, particularly outbreeding. A striking feature of this diversity is that related species often differ in pollination and mating systems, and intraspecific variation in sexual traits is not unusual, especially among herbaceous plants. This variation provides opportunities for evolutionary biologists to link micro-evolutionary processes to the macro-evolutionary patterns that are evident within lineages. Here, I provide some personal reflections on recent progress in our understanding of the ecology and evolution of plant reproductive diversity. I begin with a brief historical sketch of the major developments in this field and then focus on three of the most significant evolutionary transitions in the reproductive biology of flowering plants: the pathway from outcrossing to predominant self-fertilization, the origin of separate sexes (females and males) from hermaphroditism and the shift from animal pollination to wind pollination. For each evolutionary transition, I consider what we have discovered and some of the problems that still remain unsolved. I conclude by discussing how new approaches might influence future research in plant reproductive biology.
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Affiliation(s)
- Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.
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43
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Barrett SCH. Darwin's legacy: the forms, function and sexual diversity of flowers. Philos Trans R Soc Lond B Biol Sci 2010; 365:351-68. [PMID: 20047864 PMCID: PMC2838255 DOI: 10.1098/rstb.2009.0212] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Charles Darwin studied floral biology for over 40 years and wrote three major books on plant reproduction. These works have provided the conceptual foundation for understanding floral adaptations that promote cross-fertilization and the mechanisms responsible for evolutionary transitions in reproductive systems. Many of Darwin's insights, gained from careful observations and experiments on diverse angiosperm species, remain remarkably durable today and have stimulated much current research on floral function and the evolution of mating systems. Here I review Darwin's seminal contributions to reproductive biology and provide an overview of the current status of research on several of the main topics to which he devoted considerable effort, including the consequences to fitness of cross- versus self-fertilization, the evolution and function of stylar polymorphisms, the adaptive significance of heteranthery, the origins of dioecy and related gender polymorphisms, and the transition from animal pollination to wind pollination. Post-Darwinian perspectives on floral function now recognize the importance of pollen dispersal and male outcrossed siring success in shaping floral adaptation. This has helped to link work on pollination biology and mating systems, two subfields of reproductive biology that remained largely isolated during much of the twentieth century despite Darwin's efforts towards integration.
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Affiliation(s)
- Spencer C H Barrett
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada.
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Mitchell RJ, Irwin RE, Flanagan RJ, Karron JD. Ecology and evolution of plant-pollinator interactions. ANNALS OF BOTANY 2009; 103:1355-63. [PMID: 19482881 PMCID: PMC2701755 DOI: 10.1093/aob/mcp122] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 04/27/2009] [Accepted: 05/01/2009] [Indexed: 05/08/2023]
Abstract
BACKGROUND Some of the most exciting advances in pollination biology have resulted from interdisciplinary research combining ecological and evolutionary perspectives. For example, these two approaches have been essential for understanding the functional ecology of floral traits, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant-pollinator interactions. However, as research in these and other areas has progressed, many pollination biologists have become more specialized in their research interests, focusing their attention on either evolutionary or ecological questions. We believe that the continuing vigour of a synthetic and interdisciplinary field like pollination biology depends on renewed connections between ecological and evolutionary approaches. SCOPE In this Viewpoint paper we highlight the application of ecological and evolutionary approaches to two themes in pollination biology: (1) links between pollinator behaviour and plant mating systems, and (2) generalization and specialization in pollination systems. We also describe how mathematical models and synthetic analyses have broadened our understanding of pollination biology, especially in human-modified landscapes. We conclude with several suggestions that we hope will stimulate future research. This Viewpoint also serves as the introduction to this Special Issue on the Ecology and Evolution of Plant-Pollinator Interactions. These papers provide inspiring examples of the synergy between evolutionary and ecological approaches, and offer glimpses of great accomplishments yet to come.
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Affiliation(s)
- Randall J. Mitchell
- Department of Biology, Program in Integrated Biosciences, University of Akron, Akron, OH 44325, USA
| | - Rebecca E. Irwin
- Department of Biology, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Rebecca J. Flanagan
- Department of Biological Sciences, P.O. Box 413, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
| | - Jeffrey D. Karron
- Department of Biological Sciences, P.O. Box 413, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
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